/*
 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Kevin Lim
 */

#ifndef __CPU_EDGE_IBTB_HH__
#define __CPU_EDGE_IBTB_HH__

#include <vector>

#include "base/misc.hh"
#include "base/types.hh"
#include "config/the_isa.hh"
#include "arch/isa_traits.hh"

class DefaultIBTB
{
  private:
   typedef TheISA::ExitID ExitID;

   struct IExitPredictorEntry
   {
       unsigned iExit;
	bool hysteresis;
   };

   struct IBTBEntry
   {
       Addr target;
	bool hysteresis;
   };

  public:
    DefaultIBTB(unsigned iExitPredictorEntries, unsigned numEntries,
		unsigned iExitLength, unsigned blockShiftAmt);

    void reset();

    /**Predict. 
    *index is passed from tournament so that ibtb need not to squash.
    */
    Addr lookup(const Addr &PC, unsigned index, ExitID exitID);

    void update(const Addr &PC, unsigned index, ExitID actual_exit, Addr corr_target);

  private:	
    unsigned predictIndirectExit(unsigned index, ExitID exitID); 

    unsigned calcIExitPredictorIdx(unsigned index, ExitID exitID);

    unsigned calcIBTBIdx(Addr PC, unsigned iExit, ExitID exitID);

    Addr targetGen(Addr target, unsigned iExit);

    unsigned iExitGen(Addr target);
	
    std::vector<IExitPredictorEntry> iExitPredictor;

    std::vector<IBTBEntry> ibtb;

    unsigned iExitPredictorEntries;

    unsigned numEntries;

    unsigned iExitLength;

    unsigned idxLength;

    unsigned iExitPredictorIdxLength;

    unsigned iExitPredictorIdxMask;

    unsigned idxMask;

    unsigned iExitMask;

    unsigned blockShiftAmt; 	
};

#endif //__CPU_EDGE_IBTB_HH__
